Aqueous sol–gel synthesis, thermoanalytical study and electrical properties of La₂Mo₂O₉

Nano- and micro-sized La₂Mo₂O₉ ceramics have been successfully synthesized by an aqueous sol–gel synthesis method using a tartaric acid as a ligand. Thermal analysis of both as-prepared La–Mo–O tartrate gel precursor and La₂Mo₂O₉ double oxide heat-treated at different temperatures was performed. The high-temperature phase transition from α to β-phases was additionally investigated by broadband high-temperature impedance spectroscopy techniques. The α ↔ β phase transition was characterized by monitoring the conductivity and a transfer of heat with respect to temperature. The crystalline phase stability of monoclinic La₂Mo₂O₉ compound was confirmed by x-ray diffraction measurements, while the dense nanoscale surface composed of the particles, ranging from 50 to 100 μm, was confirmed by scanning electron microscopy.